// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#include "content/renderer/pepper/ppb_buffer_impl.h"

#include <algorithm>
#include <memory>

#include "base/logging.h"
#include "content/common/pepper_file_util.h"
#include "content/renderer/render_thread_impl.h"
#include "ppapi/c/dev/ppb_buffer_dev.h"
#include "ppapi/c/pp_bool.h"
#include "ppapi/c/pp_errors.h"
#include "ppapi/c/pp_instance.h"
#include "ppapi/c/pp_resource.h"

using ppapi::thunk::PPB_Buffer_API;

namespace content {

PPB_Buffer_Impl::PPB_Buffer_Impl(PP_Instance instance)
    : Resource(ppapi::OBJECT_IS_IMPL, instance)
    , size_(0)
    , map_count_(0)
{
}

PPB_Buffer_Impl::~PPB_Buffer_Impl() { }

// static
PP_Resource PPB_Buffer_Impl::Create(PP_Instance instance, uint32_t size)
{
    scoped_refptr<PPB_Buffer_Impl> new_resource(CreateResource(instance, size));
    if (new_resource.get())
        return new_resource->GetReference();
    return 0;
}

// static
scoped_refptr<PPB_Buffer_Impl> PPB_Buffer_Impl::CreateResource(
    PP_Instance instance,
    uint32_t size)
{
    scoped_refptr<PPB_Buffer_Impl> buffer(new PPB_Buffer_Impl(instance));
    if (!buffer->Init(size))
        return scoped_refptr<PPB_Buffer_Impl>();
    return buffer;
}

PPB_Buffer_Impl* PPB_Buffer_Impl::AsPPB_Buffer_Impl() { return this; }

PPB_Buffer_API* PPB_Buffer_Impl::AsPPB_Buffer_API() { return this; }

bool PPB_Buffer_Impl::Init(uint32_t size)
{
    if (size == 0)
        return false;
    size_ = size;
    shared_memory_.reset(
        RenderThread::Get()->HostAllocateSharedMemoryBuffer(size).release());
    return shared_memory_.get() != NULL;
}

PP_Bool PPB_Buffer_Impl::Describe(uint32_t* size_in_bytes)
{
    *size_in_bytes = size_;
    return PP_TRUE;
}

PP_Bool PPB_Buffer_Impl::IsMapped()
{
    return PP_FromBool(!!shared_memory_->memory());
}

void* PPB_Buffer_Impl::Map()
{
    DCHECK(size_);
    DCHECK(shared_memory_.get());
    if (map_count_++ == 0)
        shared_memory_->Map(size_);
    return shared_memory_->memory();
}

void PPB_Buffer_Impl::Unmap()
{
    if (--map_count_ == 0)
        shared_memory_->Unmap();
}

int32_t PPB_Buffer_Impl::GetSharedMemory(base::SharedMemory** shm)
{
    *shm = shared_memory_.get();
    return PP_OK;
}

BufferAutoMapper::BufferAutoMapper(PPB_Buffer_API* api)
    : api_(api)
{
    needs_unmap_ = !PP_ToBool(api->IsMapped());
    data_ = api->Map();
    api->Describe(&size_);
}

BufferAutoMapper::~BufferAutoMapper()
{
    if (needs_unmap_)
        api_->Unmap();
}

} // namespace content
